Integral propellant case ramjet projectile

ABSTRACT

A gun launched projectile utilizing the cartridge case as a ramjet burner. The round is loaded into the gun in normal fashion and the igniter is introduced through the rear of the cartridge case. Upon ignition the entire unit is ejected from the gun at high velocity with air inlets opening to allow ramjet engine operation.

Elite tates tent Bolick 5] Apr. 10, I973 [541 INTEGRAL PROPELLANT CASE 3,220,181 11/1965 Wolf ..60/234 RAMJET PROJECTILE 2,989,922 6/1961 Greenwood et al. ...102/49.7 2,684,570 7/1954 Nordfors 60/245 [75 Inventor: Ranse G. Bolick, Fredericksburg,

V FOREIGN PATENTS OR APPLICATIONS [73] Assignee: The United States of America as rep- 1461526 8/1954 Swede resented by the Secretary of the Navy 3,115,008 12/1963 Cohenetal. ..60/245 Primary ExaminerRobert F. Stahl Attorney-R. S. Sciascia and Thomas 0. Watson, Jr.

57 ABSTRACT I A gun launched projectile utilizing the cartridge case as a ramjet burner. The round is loaded into the gun in normal fashion and the igniter is introduced through the rear of the cartridge case. Upon ignition the entire unit is ejected from the gun at high velocity with air inlets opening to allow ramjet engine operation.

10 Claims, 1 Drawing Figure PATENTED 3.726.219

INVENTOR RANSE G. BOL/CK ATTORNEY INTEGRAL PROPELLANT CASE RAMJET PROJECTILE STATEMENT OF GOVERNMENT INTEREST The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

BACKGROUND OF THE INVENTION The present invention relates to gun launched projectiles and more particularly to such projectiles that are converted to ramjet operation after launch.

Typical prior art gun launched projectiles utilize no further propulsion after launch from the gun. Consequently, the range is limited by the velocity obtained at launch. Some specialized projectiles can use rocket or ramjet propulsion as a means of increasing or maintaining velocity to obtain greater ranges. These projectiles typically have their rocket motors or ramjet burners located within a substantial portion of the projectile payload volume. When this is taken from the payload volume the payload weight is greatly reduced. Therefore system efficiency suffers while the range performance increases.

SUMMARY OF THE INVENTION The present invention provides an efficient weapon concept which can achieve the advantages of air breathing propulsion without an appreciable reduction in payload size and weight. The cartridge casing (normally a waste unit) is converted into a useable booster rather than being discarded after firing. The relatively large volume of the cartridge casing enables more efficient ramjet combustion and reduces the amount of conventional projectile volume which is devoted to propulsion after launch.

OBJECTS OF THE INVENTION Accordingly, it is an object of the present invention to provide a gun launched projectile having increased range capabilities without a general reduction in system efficiency.

Another object is to provide a system to increase the range and/or velocity of a gun launched projectile at a minimum weight and volume increase.

A further object of the invention is the provision of a gun launched projectile having ramjet post-launch capabilities without the usual payload weight reduction.

Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS The single FIGURE of the drawing shows a crosssection of a preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The drawing illustrates a projectile payload l and a cartridge case 11 crimped or otherwise attached at 12 to the projectile l0. Cartridge case 11 has an operating inlet 13 which is opened during exit from the gun to admit air to the ramjet engine burner. An obturator ring 14 seals the projectile case combination during launch. A nozzle configuration 15 is located on the rear portion of cartridge case 11 and is sealed by a disc membrance 16.

The wall 17 of cartridge case 11 confines the propellant for initial launch within space 18 and acts as the burner wall after exit. Ramjet fuel can be contained in the center extension to the projectile 19 (although other locations could be utilized) and injected into the burner if liquid or burned if solid to provide propulsion. After launch, space 18 contains combustion products of the ramjet fuel.

To fire, the round is loaded into the gun in a normal fashion. After loading an ignitor is introduced through the closure membrane 16 and ignited. The propellant, within space 18, is consumed producing pressure which causes the entire unit to be ejected from the gun at high velocity. Upon ejection the inlet 13 is opened which admits air into the ramjet engine.

The burning of the initial propellant charge, in the space 18, causes the ramjet fuel, within the central extension 19, to be heated above its ignition temperature. Thereafter air entering through operating inlet 13 will cause the fuel to burn. In the alternative, the ramjet fuel may be ignited by an ignitor. With ignition of the ramjet fuel, the engine continues to operate in a normal ramjet mode until:exhaustion of the fuel, the projectile travels above the atmosphere, or automatic shut down.

Although the design shown is based on a spin type projectile, tin or other stability methods could be used. Payload design is unlimited as to shape, size and weight and may be varied for various diameters and/or missions. Solid, liquid and gaseous fuels may be used in the ramjet engines following conventional techniques.

The drawing depicts the casing as being larger than the payload. This however is intended as an illustration only as the inlets 13 could be replaced with flip out inlets and thereby permit reduction of the casing to the same diameter as the payload. Further, the fuel is shown contained within an extension into space 1.8. As an alternative, a highly inhibited fuel could be placed around the periphery of the casing on the side walls 17, or at other positions, and be burned as ramjet rather than launch fuel. Additionally, the closure at 16 could be of conventional design having a weak separation line at a position which would cause good launch characteristics. The separated portion would remain within the gun chamber and would have to be extracted. A further alternative would implement the use of a fragmenting obturator to seal both the gun gases and the ramjet engine inlets at 13. These would be thrown off at exit.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings.

What is claimed is:

1. In a gun launched projectile having a payload and a permanently attached cartridge case the combination which comprises:

ramjet fuel and gun propellant both contained within said cartridge case;

operating inlet means located in the side wall of said cartridge case; and

a first means for sealing said inlet means until launch and thereafter opening said inlet means to permit an air flow to the ramjet fuel;

whereby ignition of the gun propellant will launch the projectile and heat the ramjet fuel above its ignition temperature in a manner which causes the ramjet fuel to burn upon the opening of the inlet means.

2. The combination of claim 1 wherein the said first sealing means comprises an obturator ring.

3. The combination of claim 1 wherein the ramjet fuel is contained within a center extension to the projectile payload and the inlet means are located on the end of the cartridge case adjacent to the projectile payload.

4. The combination of claim 3 wherein the ramjet fuel is a solid fuel.

5. The combination of claim 3 which further comprises:

nozzle means located within the cartridge case on the end furthest from the projectile payload; and

a second means located adjacent said nozzle means for sealing the rear portion of said cartridge case before launch and opening upon launch.

6. The combination of claim 5 wherein the second sealing means comprises a disc membrane.

7. The combination of claim 1 wherein said cartridge case has a single chamber containing said ramjet fuel and gun propellant.

8. The combination of claim 1 wherein said gun propellant is a liquid.

9. The combination of claim 1 including an igniter for igniting the gun propellant.

10. The combination of claim 1 wherein the portion of said cartridge case originally containing said gun propellant forms a combustion chamber for said ramjet fuel. 

1. In a gun launched projectile having a payload and a permanently attached cartridge case the combination which comprises: ramjet fuel and gun propellant both contained within said cartridge case; operating inlet means located in the side wall of said cartridge case; and a first means for sealing said inlet means until launch and thereafter opening said inlet means to permit an air flow to the ramjet fuel; whereby ignition of the gun propellant will launch the projectile and heat the ramjet fuel above its ignition temperature in a manner which causes the ramjet fuel to burn upon the opening of the inlet means.
 2. The combination of claim 1 wherein the said first sealing means comprises an obturator ring.
 3. The combination of claim 1 wherein the ramjet fuel is contained within a center extension to the projectile payload and the inlet means are located on the end of the cartridge case adjacent to the projectile payload.
 4. The combination of claim 3 wherein the ramjet fuel is a solid fuel.
 5. The combination of claim 3 which further comprises: nozzle means located within the cartridge case on the end furthest from the projectile payload; and a second means located adjacent said nozzle means for sealing the rear portion of said cartridge case before launch and opening upon launch.
 6. The combination of claim 5 wherein the second sealing means comprises a dIsc membrane.
 7. The combination of claim 1 wherein said cartridge case has a single chamber containing said ramjet fuel and gun propellant.
 8. The combination of claim 1 wherein said gun propellant is a liquid.
 9. The combination of claim 1 including an igniter for igniting the gun propellant.
 10. The combination of claim 1 wherein the portion of said cartridge case originally containing said gun propellant forms a combustion chamber for said ramjet fuel. 